About the Jomon culture in Hokkaido

In Hokkaido, there are over 7,000 sites of Jomon period living that have been discovered. There are various different features depending on the region.
How did these differences and features come about? Let’s first learn about the origin of the Hokkaido island and its nature.

The origin of the Hokkaido island

Hokkaido is an island located between 41 and 45 degrees north latitude and the size of the main island is about 78,000 km2. It is the 21st largest island in the world after Ireland. Since when does this vast land exist?

About 80 million years ago, Hokkaido used to be part of the Eurasian continent. Ammonite and other ancient creatures lived in the ocean to the east of the continent. The geological layers from this era can be found in various parts of Hokkaido today, including Mikasa City, Mukawa Town, and Nakagawa Town.

The plates that made up the earth of the eastern half of Hokkaido and the western half of Hokkaido gradually came closer due to their movements. By about 50 million years ago, the faults at their boundaries started to collide.

Around 45 million years ago, the western half of Hokkaido and the eastern half of Hokkaido came even closer, turning wide areas into shallow ocean or land. There were vast areas of wetlands and forests. Fallen trees accumulated in the shallow coastal region ocean. These eventually turned into the coal produced in Sorachi and Kushiro regions.

The western/eastern half and the central part of Hokkaido formed Hokkaido’s current shape after a long time about 20 million years ago. The ocean floors of the Sea of Japan and the southern Sea of Okhotsk continued to expand. There was vast ocean around Hokkaido.

Then, about 3 million years ago, ocean water entered the lowland regions, such as Tokachi Plain and Ishikari Plain, creating an inlet.

About several hundred thousand years ago, the ice age and warm period started to alternate. In the last ice age 20,000 years ago, the ocean surface dropped by about 120 meters, connecting Hokkaido, Sakhalin and Kuril Islands by land. Animals and plants travelled to Hokkaido from the continent, including mammoths, Naumann elephants, and giant deer.

After that, Earth started to gradually warm up until the present day. The sea surface rose and Hokkaido became an island again. Northern animals, such as pikas, continue to live in the present day living in cool regions, such as places with wind holes like Lake Shikaribetsu and tall mountains.

参考：北海道博物館第2回特別展『ジオパークへ行こう！　―恐竜、アンモナイト、火山、地球の不思議を探す旅―　展示・ジオパークまるわかりガイドブック』

Uchiura Bay (Volcanic Bay) and volcano

In Japan, there are 111 active volcanoes (as of February 2023), and 20 of them are in Hokkaido. Hokkaido’s volcanoes are not evenly distributed. They are concentrated in 3 regions: the southwest Hokkaido volcano region, the Taisetsu/Tokachi/Shikaribetsu volcano region, and the Akan/Shiretoko volcano region.

Let’s look at the southwest Hokkaido volcano region where there are world heritage sites that include constituent and related assets.

There is a bay called Uchiura Bay in this volcanic region surrounded by water in three directions from the north, west, and south of Hokkaido’s southwest region and Oshima Peninsula. Cold water flows into Uchiura Bay in spring (Oyashio water) through the Hidaka coast from the north. In the fall and winter, warm water flows in from the south (Tsugaru warm water). As a result of this, cold and warm water alternate by season. The Bay also offers a rare place where the two types of water mix, creating rich aquatic resources.

On the other hand, Uchiura Bay is also well known in Hokkaido as a “volcanic bay.” The shape of the bay is circular and the bay is called “volcanic,” so many people initially think it’s an ancient volcanic crater. However, no such evidence has been found in the past. The reason why this bay came to be called the Volcanic Bay is because a captain of a foreign ship visited this region at the end of the 18th Century and found plumes rising from Mt. Esan, Mt. Komagatake, and Mt. Usu. As these mountains were close to the bay, he named the bay, “Volcanic Bay.”

Being close to volcanoes comes with a history of natural disasters. For example, a major eruption of Mt. Komagatake in 1640 collapsed the mountain and caused debris avalanches falling into Uchiura Bay. This caused tsunami that drowned about 700 people.

Uchiura Bay teaches us the important lesson that disasters and rich nature are two sides of the same coin.

Origin of the Hokkaido flora

The Japanese archipelago stretches from the south to the north, with wide-ranging climates that include the cold subarctic zones, cold-temperate zones, warm-temperate zones, and subtropical zones. Plants and animals that have adapted to each zone can be found. Hokkaido is the northernmost region of Japan, so the flora here matches the cold climate, which is different from Honshu.

Let’s look at the current natural flora of Hokkaido. On the southwestern side, you can find deciduous broad-leaved forests (temperate deciduous forests), such as beech found in cold-temperate zones. On the northeastern side, you can find subarctic coniferous forests, such as Sakhalin fir, Yezo spruce, and Sakhalin spruce. These are mixed with cool temperate deciduous broad-leaved trees. The two types of trees are naturally mixed. However, this has not been continuous throughout the history.

25,000 years ago was the near end of the last glacial period (the coldest period of the last glacial period). Hokkaido at the time had deciduous and coniferous forests composed of Gmelin larch and Siberian dwarf pine. The forest was similar to the Siberian Gmelin larch forests today. After that, the climate became warmer. About 12,000 years ago, Hokkaido had evergreen coniferous forests composed of Yezo spruce and Sakhalin fir trees. About 8,000 years ago, the number of deciduous broad-leaved trees, such as Mizunara and Japanese elm. These were mixed with Sakhalin fir, creating deciduous-coniferous mixed forests that can be found today. Deciduous broad-leaved trees, such as Manchurian walnut trees, Mizunara, and amur cork trees were precious natural food resources that supported the lives of the Jomon people.

日本列島の自然植生（「日本の植生、宮脇昭　編、昭和52年」を改変）
出典：「植生・植生図について」(環境省生物多様性センター) (http://gis.biodic.go.jp/webgis/sc-009.html)

Origin of the Hokkaido fauna

Many animals that are not found in Honshu live in Hokkaido, such as brown bears and pikas. On the other hand, common animals in Honshu like Asian black bears and Japanese monkeys are not found in Hokkaido. There is a major difference in fauna between Hokkaido and Honshu and this biodistribution boundary between Hokkaido and Honshu is called the Blakiston Line.

This difference was caused by the frequent climate changes that repeated throughout our planet’s history.
Currently, Hokkaido is an island. However, there were times when it was connected by land during cold eras and there were times when it was an island during warm periods. Terrestrial plants can carry themselves across the sea by distributing their seeds using the wind. However, land animals can only expand their biodistribution through physical traveling only. As a result, being connected to land was a critical matter that determined whether an animal species could continue to exist.

Until the last glacial age that ended 10,000 years ago, the Soya Strait that divided Hokkaido from Sakhalin was connected by land, and the Tartar Strait that divided Sakhalin and the Eurasian continent was connected by a land bridge. It is considered that mammoths and giant deer traveled from the continent to Hokkaido using these land bridges. On the other hand, the Tsugaru Strait that divided Honshu and Hokkaido were much deeper than the other straits at about 140 meters deep. Even during the last glacial age, no land bridge was formed, limiting the travel of land animals.

Pictures provided by: Engarucho Board of Education

Hokkaido before the Jomon period

Hokkaido was shaped as part of our planet’s great activities.
When did people come to Hokkaido and how did they live?
Let’s look at how people lived in Hokkaido before the Jomon period, analyzed from Hokkaido’s ruins and natural environments at the time.

Hokkaido before the Jomon period

The oldest ruins in Hokkaido dates back to about 30,000 years ago. People lived in Hokkaido from the paleolithic age, before the Jomon period.

Looking at the history of the Earth in the last million years, the planet alternated between glacial periods (cold eras) and interglacial periods (warm eras) in 10,000 year intervals. 25,000 years ago was the coldest time of the last glacial period with developed glaciers in the arctic and the northern hemisphere. This made the ocean shallower by about 120 meters compared to today.

The climate connected Hokkaido, Sakhalin, and the Eurasian continent by land. Hokkaido was a large peninsula sticking out from the continent.
The cold and dry climate created nature similar to the present-day alpine zone. This meant that there were few plant natural resources. People followed mammoths and giant deer that came from the continent. They were nomadic hunters.

Warming climate and changes to the natural environment

About 16,000 years ago, the climate started to warm and the sea level gradually rose, turning Hokkaido into an island like it is present day.

The rising sea level widened the straits, which allowed a large amount of warm Tsushima sea current to flow into the Sea of Japan. In addition, the Japan current traveled north to the Pacific Ocean. The sea currents surrounding the Japanese archipelago changed. This warm current created vapors that brought rain and snow to the archipelago bring about the present day warm and moist climate.

Nuts, such as acorns and walnuts grew in the mountains. Salmon and trout swam up the river. Many types of sea creatures started to live. Large animals like mammoths went extinct and small/medium sized animals like deer and boar flourished.

People gradually adapted to the changing environment. They started using earthenware for boiling food, developed bows and arrows for hunting small/medium-sized animals, and started using fishing tools like fishing hooks. They started to make villages and started to live a “sedentary life.” This was the beginning of the Jomon Period.

Characteristics of the Jomon period

Jomon period started in the changing natural environment caused by the warming climate. It spread to the entire Japanese archipelago.
How did people live in the Japanese archipelago that stretched from the south to the north? Did people in distant regions interact with each other, such as the people in Hokkaido and the people in Honshu?
Let’s explore the clues from the ruins to find out about the lives and culture of the people during the Jomon period.

Characteristics of the Jomon period

The biggest characteristic of the Jomon period was the fact that people achieved a “sedentary life.” It may seem natural in the present day to be settled. However, in the course of human’s history, the “nomadic period” when humans hunted was much longer. Being settled was a major turning point in the history of humanity.

Globally, sedentary life started after people became able to cultivate nature for farming and stock-raising which enabled increased production and storage of food. In comparison, the sedentary life during the Jomon period was based on hunting, fishing, and collecting food. They achieved a sedentary lifestyle without significantly altering nature. This was unique compared to other prehistoric cultures.

Life during the Jomon period

To sustain villages, villagers needed a system to secure enough food for villagers, process/preserve the food, and dispose of food wastes like bones and shells as well as unneeded tools. People in the Jomon period observed nature around them like the ocean, mountain and river, and gained food available during various different seasons.

They built storage holes for preserving food for a long period. They also built shell mounds and earth mounds where they used food wastes and tools for rituals and festivals.

Spiritual culture during the Jomon period

How did the Jomon people think about nature and their society? The Jomon spiritual culture can be found in the ruins and remains. Graves of family members, ancestors, and the deceased were buried with combs, bracelets, and lacquered items.

Shell mounds and earth mounds may seem to us now like disposal grounds. However, these sites contained graves, intentionally destroyed tools, and clay figures. It is considered that these sites were also ritual grounds. Stone circles using stones as big as the human head have been found. Some of them contained graves and are suspected to be related to the nearby symbolic mountains or sun movements. These offer us insights into the worldview of the people at the time.

Technology and interaction during the Jomon period

People during the Jomon period could use advanced techniques to lacquer combs and earthenware. They could also process hard jade stones to make accessories. In particular, their lacquerware is one of the oldest in the world, made about 9,000 years ago (Kakinoshima ruins B). They also had the technology to use natural asphalt as adhesives.

It is known that lacquer, jade, and asphalt came to Hokkaido across the Tsugaru Strait. Meanwhile, Honshu received from Hokkaido arrowheads (flint arrowheads), obsidian for making knives, and a type of greenstone (Aotora stone) for making stone axes. These show there were interactions and trades across the ocean.

Characteristics by region

Currently, in Japan, there are different characteristics by region: Hokkaido, Tohoku, Kanto, Kansai, Kyushu, and Okinawa. Likewise, the Japanese archipelago also had different characteristics by region.

The regional characteristics are reflected in the shape and pattern of crafted earthenware. Pit dwelling, graves, and stone circles also have region-specific similarities. It is considered that lifestyles and spiritual characteristics were region specific.

One of the reasons why different cultures were formed depending on the region was the difference in the natural environments of the thin Japanese archipelago that stretches from the south to the north. Different climates in the north and the south created different types of forest with different ecosystem of animals and plants. Differences in animals and plants that offer food, wood that offer building materials, and stones and clay that offer materials for stone tools and earthenware affected regional lives and culture differently.

Similarities between the culture in Hokkaido and the regional culture in northern Tohoku

The Tsugaru Strait divides the southern edge of Hokkaido and the northern edge of Honshu, connecting the Sea of Japan and the pacific ocean. This is the Blakiston line dividing animals like brown bears and Asian black bears.

Although the Tsugaru Strait divided the plants and animals living to the north of the line and the south, there were also similarities between the north and the south. For example, the forests of both the north and the south were cool temperate deciduous broad-leaved forests (northern beech area). Jomon villages in both regions had oak trees that produced acorns, Mizunara, and beech trees producing edible nuts. Both region also had mixture of warm and cold currents with cold current fish, such as salmon and trout, and warm current fish, such as tuna and yellowtail.

During the Jomon period, common regional cultures were found in the southern part of Hokkaido and the northern part of Tohoku, reflected in the Jomon ruins. In particular, about 4,500 to 5,500 years ago, there was a common regional culture sphere called the “cylindrical earthenware culture” derived from uncovered cylindrical earthenware. There were strong similarities in terms of the lifestyle and the spiritual culture.

History of Hokkaido after Jomon period

To the south of Honshu, the continent brought about rice cultivation, and the Yayoi period began. In comparison, what kind of history and culture did Hokkaido have at the time?
Let’s look at the history of Hokkaido after the Jomon period that was formed through interacting with other regions.

Yayoi and continued Jomon culture

About 3,000 years ago, rice cultivation came to northern Kyushu from the eastern parts of the continent and the Korean Peninsula. Yayoi culture, using bronze and iron tools, spread in the Japanese archipelago. By 2,400 years ago, rice cultivation reached the northern part of the Tohoku region, and the Jomon culture came to an end. Hokkaido inherited the Jomon culture of a hunter and gatherer’s society, in a “continued Jomon culture.” Rice cultivation did not start in Hokkaido not only because of its cool climate but also because its nature was rich.

In the first half of the continued Jomon culture, some regions of Hokkaido had connections to the Yayoi culture in Honshu and the continent to the north. In the latter half, there were vibrant interactions with the Tumulus culture in Honshu. Iron tools were introduced and stone tools went out of trend. However, Jomon patterns continued to be used on earthenware because of the tradition preserved from the Jomon era.

Okhotsk and Satsumon culture

Around the 5th Century, people traveling south from Sakhalin settled in the northern part of Hokkaido and the coastal areas of the Sea of Okhotsk. They left behind the Okhotsk culture based on fishing and hunting sea animals. They had iron tools derived from the continent’s Mohe culture which differed greatly from the continued Jomon culture.

Around the 7th Century, Honshu adopted the Ritsuryo legal codes. Meanwhile, in the south and central regions of Hokkaido, the Satsumon culture was formed. Earthenware influenced by Haji pottery in Honshu stopped using Jomon patterns. People started living in pit dwellings with a furnace like in Honshu. Farming of grains like foxtail millet and Japanese millet also began.

Around the 9th and 10th Century, the Satsumon people spread to the northeastern part of Hokkaido and expanded to the coastal areas of the Sea of Okhotsk, an area of Okhotsk culture. The two cultures met and merged to form the Tobinitai culture producing earthenware and residences with characteristics from both cultures.

Hokkaido continued to have unique history and culture

Around the 12th to 13th Century, Kamakura Shogunate was established in Honshu. National distribution networks were established to distribute products from different regions widely. Hokkaido started to get iron pots (with inner handles that can be used to hang it from a house’s ceiling) from Honshu, which became popular.

With this, earthenware that had been used for boiling since the Jomon period gradually became less common. Pit dwellings also shifted to buildings on land. Archaeologically, this was the time when Ainu culture’s features can be found.

Looking at the map, Hokkaido is located where the Sea of Japan and Sea of Okhotsk’s inland sea intersect. Hokkaido was located in an area where diverse culture met in a big world of northeastern Asia and east Asia. It has always had unique history and culture outside that of Japan.